This is not a joke: A wellness biohack called “testicle tanning” is hot stuff right now — at least according to an unusual guest on Tucker Carlson’s latest special.

Carlson is very concerned about The State Of Men. So much so that he produced a TV special called The End of Men, which aired over the weekend on Fox News. Testosterone levels are dropping, according to the anchor and heir to the Swanson frozen-food fortune. This is why society as we know it is on the verge of collapse, he says.

What can men do to preserve our social structures, the American dream, and restore our bedraggled society to its previous glory, according to Carlson? Tan their balls, of course!

Carlson’s guest, Andrew McGovern, a personal trainer at a gym in Ohio, touted the practice on the special as “bromeotherapy.” Homeopathy, but for BROS. Ball tanning involves someone exposing their scrotum to infrared light. Soon, their balls will be toasty, testosterone levels will skyrocket, McGovern claims, and the newly-remanned man can walk around crushing cinderblocks with their bare hands, or something.

Actual urologists, however, are quick to note that there are more than a few scientific flaws to this theory.

Jesse Mills is the director of UCLA’s Urology department at Santa Monica, a male reproductive health specialist, and the author of A Field Guide to Men’s Health: Eat Right, Stay Fit, Sleep Well, and Have Great Sex—Forever.

“I can only imagine the quantity of double-dank diesel Tucker’s producer was smoking to get this guy on his show,” Mills tells Inverse.

Does scrotum tanning increase testosterone?

In the segment, McGovern claims there’s “so much data” supporting infrared testicle tanning. Ashley Winter, a board-certified urologist took to Twitter to unequivocally refute the claim:

“THERE IS NOT ‘SO MUCH DATA ON TESTICLE TANNING’” she writes, “THERE IS NO DATA ON TESTICLE TANNING.”

In part, Winter explains, it’s actually impossible to tan one’s testicles.

“You cannot tan an internal organ,” she says. “Tanning your scrotal sack and calling it ‘testicle tanning’ is like tanning your abdominal skin and calling it ‘liver tanning.’”

But is there any data supporting the use of infrared light on one’s scrotum?

“Maybe red light therapy to the scrotum reduces redness of the scrotal skin, I dunno. It does NOT penetrate the dartos, tunica vaginalis, and tunical albuginea of the testes & stimulate testes production of testosterone. That is complete and utter garbage that zero data supports,” Winter tweets.

Mills says McGovern may have gotten the idea that infrared light increases testosterone from a very small, very old study that, Mills says, “has no real science to it.”

In 1939, a study of about eight men showed that if they exposed their testicles to intense sunlight, their testosterone went up dramatically. However, Mills says, “there was no control group, the study has never been replicated, there’s no real science at all.”

One thing we know, Mills says, is that testosterone levels fluctuate dramatically throughout the day.

“In a young, healthy male, testosterone levels can vary by 100 points a day,” he says. “So if you check the testosterone levels of a 25 or 30-year-old guy at 4 p.m., it might be something like 250 nanograms per deciliter. Then if you check it the next morning at like 4 or 5 am it could be 400.

“If you check your testosterone levels 12 hours apart you might have a huge increase even if you didn’t put your balls in front of an infrared light.”

Mills isn’t completely ruling out the possibility that exposing one’s scrotum to infrared light has an effect on testosterone — but currently, there’s no good science supporting the idea.

Low testosterone and the explosion of “bro-science”

The idea of a “normal testosterone” range is a “little bit artificial,” Mills says.

“Our medical guidelines say that a normal range starts at around 300 nanograms per deciliter, which is relatively standard,” he says.

“And the normal range actually goes up to about 1000. So you’ve got this 700-point delta — that’s a lot of wiggle room.”

Mills believes those kinds of medical establishment guidelines may contribute to what Mills calls “bro-science”: A desire among certain men to “biohack” their bodies to be the most optimized version of themselves using unproven medical theories and treatments.

And the medical establishment may have some culpability there, Mills says.

“If I see ten guys who have symptoms of low [testosterone] like decreased libido and not getting as jacked at the gym, maybe five of them will have testosterone levels in the upper normal range,” he says.

“A lot of doctors will just say they’re in a normal range and send them on their way. That can make a lot of men turn to these other practices that might not have any effect, or could be harmful.”

While it’s important for the medical establishment to address those symptoms even if a man’s testosterone levels are within a typical range, it’s important to understand that there are reasons doctors don’t just prescribe testosterone replacement therapy when it’s not indicated.

“I think the biggest risk of testosterone therapy that I worry about with these guys… is that it can cause you to be infertile,” he says.

Something else that can cause infertility is the testicles being “too hot for too long,” Mills adds.

“Let’s say that testicular tanning does actually improve your [testosterone] levels by anywhere from 30 to 200 percent — if you’re quoting a study that was never a real study in the first place — we don’t know what’s happening to those sperm counts.”

“If you’re improving your testosterone by killing your sperm, that may be one of these bro-science things, which actually may do more harm than good.”

Ultimately, Carlson’s premise is fundamentally flawed. A lack of testosterone is not responsible for the collapse of society, nor is more testosterone inherently better, or healthier for men.

If you’re experiencing symptoms of low testosterone like fatigue, low libido, and difficulty building muscle when working out, you can see a doctor. If you’re told you’re levels are within a typical range, don’t stick your balls in front of infrared light — instead, ask your doctor for help to figure out what else may be going on.